[PATCH] D51519: [SimpleLoopUnswitch] remove a chain of dead blocks at once

[Alina Sbirlea via Phabricator via llvm-commits]

asbirlea added inline comments.


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Comment at: lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:1387
+                                                ExitBlocks.end());
+  for (Loop *ParentL = &L; ParentL; ParentL = ParentL->getParentLoop()) {
+    DeathCandidates.append(ParentL->blocks().begin(), ParentL->blocks().end());
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Do we need to go over all parent loops now? Processing the successors of each block in DeathCandidates may be enough. It at least resolves testcase `delete-dead-blocks.ll` which motivated processing blocks in parent loops.


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Comment at: lib/Transforms/Scalar/SimpleLoopUnswitch.cpp:1389
+    DeathCandidates.append(ParentL->blocks().begin(), ParentL->blocks().end());
+    while (!DeathCandidates.empty()) {
+      auto *BB = DeathCandidates.pop_back_val();
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Could we pull the while outside the for loop?
And populate the initial DeathCandidates with ExitBlocks and loop blocks?


Repository:
  rL LLVM

https://reviews.llvm.org/D51519